1. Sensation and Perception

2. Grab a scrap sheet of paper
Write down your definition of
sensation
perception

3. Sensation
The process by which our sensory systems (eyes, ears, and other sensory organs) and nervous system receive stimuli from the environment
A person’s awareness of the world

4. Sensation Input comes from the five senses: Visual (Eyes)
Hearing (Ears)
Touch (Skin)
Smell (Nose)
Taste (Tongue)

5. The process of integrating, organizing and interpreting sensations.
Perception
The process of integrating, organizing and interpreting sensations.

6. Sensory Receptors
Specialized cells unique to each sense organ that respond to a particular form of sensory stimulation.

7. Sensory Receptors: Example
A combination of your senses. When you bite into a crisp apple, you hear the crunch, you taste the sweetness, you feel the smooth skin, you see the red, and you smell the aroma.

8. Transduction
The process by which a form of physical energy is converted into a coded neural signal that can be processed by the nervous system.

9. What is a Threshold?

10. Threshold An edge or a boundary
Walking into the room – on one side you are in the room on the other you are outside of the room

11. Absolute Threshold
The smallest possible strength of a stimulus that can be detected half the time.

12. Absolute Threshold Example
Touch: The wing of a bee falling on your cheek from a height of 1 centimeter

13. Absolute Threshold Example
Hearing: The tick of a watch from 6 meters away

14. Absolute Threshold Example
Taste: 1 gram of table salt in 500 liters of water – the minimum needed to taste something

15. Absolute Threshold
Vision: A candle flame on a clear night, 30 miles away – the minimum needed to see it. Doesn’t mean that you can make out what it is

16. Absolute Threshold Example
Smell: 1 drop of perfume in a 3 room house.

17. Weber’s Law
The greater the magnitude of the stimulus, the larger the difference must be in order to be noticed

18. Examples When you can detect the difference in volume of music
When you can detect the difference in pressure on your arm

19. Weber’s Law Example
If you are carrying 20 lbs. and add 5 lbs., it’s noticeable. If you are carrying 100 pounds and add 5 pounds, it may not be noticeable. You need to add 10 lbs. to 100 pounds to make it noticeable.

20. Just Noticeable Difference Threshold
The minimum difference that a person can detect between two stimuli 50% of the time.

21. Sensory Adaptation
When exposed to a stimuli over a period of time there will be a diminished sensitivity to it
If a stimulus is constant and unchanging, eventually a person may fail to respond to it

22. Example of Sensory Adaptation
A hot tub – after a certain period of time no longer seems as hot

23. Selective Attention
Focusing conscious awareness on a particular stimulus (sense) to the exclusion of others

24. Selective Attention Example
Walking down the hallway – all 5 senses are firing. What grabs your attention?